Introduction to Fungi, Third Edition

MYXOMYCETES: TRUE (PLASMODIAL) SLIME MOULDS
53
Genetic studies have shown that fusion occurs
between plasmodia of genetically closely related
strains (Carlile & Dee, 1967). The type of incompatibility
brought about by the interaction of
genetically distinct plasmodia is an example
of a widespread phenomenon called vegetative
incompatibility which is found not only in
slime moulds, but also in the Eumycota, vertebrates
and other organisms. In humans, a similar
phenomenon accounts for blood grouping or
the failure of tissue transplantations. It is interesting
to consider the paradox that fusion
between genetically dissimilar myxamoebae is
encouraged during sexual reproduction by the
existence of different mating types, whereas
it is discouraged during vegetative fusion of
plasmodia.